The 1964 U.S. National Championships (now known as the US Open) was a tennis tournament that took place on the outdoor grass courts at the West Side Tennis Club, Forest Hills in New York City, United States. The tournament ran from 2 September until 13 September. It was the 84th staging of the U.S. National Championships, and the fourth Grand Slam tennis event of 1964.
See main article: 1964 U.S. National Championships – Men's singles. 
Roy Emerson defeated Fred Stolle 6–4, 6–1, 6–4
See main article: 1964 U.S. National Championships – Women's singles. 
Maria Bueno defeated 
Carole Caldwell Graebner 6–1, 6–0
Chuck McKinley / Dennis Ralston defeated 
Graham Stilwell / Mike Sangster 6–3, 6–2, 6–4
Billie Jean Moffitt / Karen Susman defeated Margaret Smith / Lesley Turner 3–6, 6–2, 6–4[1]
Margaret Smith / John Newcombe defeated Judy Tegart / Ed Rubinoff 10–8, 4–6, 6–3